1. Field of the Invention
The present invention generally relates to a protein stabilizer, a protein composition, a method for stabilizing a protein, and a kit containing a protein composition.
2. Description of Related Art
It is generally known that the function of a protein such as an enzyme is dependent on its higher order structure (or conformation). If its higher order structure is broken down for some reason, the original function may be lost or its catalytic activity may decrease. On the other hand, protein is mostly stored in a lyophilized form, and various lines of research have been performed to prevent loss of function and to preserve catalytic activity during the lyophilized process. For example, it is known that the following materials are useful as protein stabilizers: amino acids, such as sodium glutamate; proteins, such as albumin and skim milk; saccharides, such as sucrose and maltose; reducing agents, such as glutathione and mercaptoethanol; polyols, such as glycerol and sorbitol; and surfactants, such as Tween 80 and Brij 35.
As described above, amino acids, proteins, saccharides, reducing agents, polyols, and surfactants are well-known stabilizers for protein. In some cases, different combinations of amino acids, saccharides, reducing agents, polyols, and surfactants with a protein do not have sufficient effect on its stabilization. In contrast, bovine serum albumin is a protein stabilizer that does have sufficient ability to stabilize various proteins, and thus can be readily used as a protein stabilizer.
However, most of the proteins used for a protein stabilizer are obtained from quadrupeds such as cattle, and there is a possibility that the protein stabilizer will be contaminated with pathogens of the animals such as bovine spongiform encephalopathy (BSE) or foot-and-mouth disease. Therefore, a novel, safe and excellent protein stabilizer without contamination of pathogens is desired.
[Patent document 1] Japanese Patent Publication NO. 1985-280523.
[Patent document 2] Japanese Patent Publication NO. 1987-149628.
[Patent document 3] Japanese Patent Publication No. 2000-507819 (Japanese translation of PCT international application).
[Patent document 4] Japanese Patent No. 3343712.